Shelby County’s residents are the healthiest in Alabama, reports a national study by the University of Wisconsin Population Health Institute and the Robert Wood Johnson Foundation.

Perry County in southwest Alabama has been deemed the home of the state’s least healthy residents.

Alabama’s 10 healthiest counties are, in order of healthiest, Shelby, Lee, Baldwin, Madison, Morgan, Limestone, Elmore, Houston, Coffee and Blount. The 10 counties whose residents are in the poorest health, starting with the least healthy, are Perry, Greene, Walker, Lowndes, Bullock, Dallas, Sumter, Wilcox, Fayette and Marengo.

The report shows the healthiest counties in the state are clustered in the northern region of the state, the least health in the southern and central regions.

Those are the findings of the study, “County Health Rankings,” the first to rank the overall health of the counties in all 50 states by using a standard formula to measure how healthy people are and how long they live, said a press release from those who conducted the research.

“This report shows us that there are big differences in overall health across Alabama’s counties, due to many factors, ranging from individual behavior to quality of health care, to education and jobs, to access to healthy foods and to quality of air,” said Patrick Remington, M.D., M.P.H., associate dean for public health at the University of Wisconsin’s School of Medicine and Public Health.

“For the first time, every person can compare overall health of their county to the health of other counties in Alabama, and also see where they state needs to improve.

The report is available online at Countyhealthrankings.org.

Researchers used five measurers to assess the level of overall health or “health outcomes” for Alabama by county: the rate of people dying before age 75, the percentage of people who report being in fair or poor health, the numbers of days people report being in poor physical and poor mental health, and the rate of low-birth-weight infants.

The report also looked at factors like health behavior, clinical care, social and economic factors and physical environment.

Health factors studied included rates of adult smoking, adult obesity, binge drinking and teenage pregnancy; the number of uninsured adults, availability of primary care providers and preventable hospital stays; rates of high school graduation, number of children in poverty; homicide rates, access to healthy foods, air pollution levels and liquor store density.

“These rankings demonstrate that health happens where we live, learn, work and play. And much of what influences how healthy we are and how long we live happens outside the doctor’s office,” said Risa Lavizzo-Mourey, M.D., M.B.A., president and CEO of the Robert Wood Johnson Foundation. “We hope the County Health Rankings spurs all sectors — government, business, community and faith-based groups, education and public health — to work together on solutions that address barriers to good health and help all Americans lead healthier lives.”